(1) Field of the Invention
The invention relates to a pre-formed tooth crown, and more particularly to which is designed for prosthesis in dentistry and can be easily used to construct a crown bridge by joining multiple tooth crowns.
(2) Description of the Prior Art
Prosthesis in dentistry is a crucial and professional therapy process, which can retrieve the normal teeth function by wearing a tooth restoration. However, during the therapy, the work in constructing a tooth restoration usually takes lots of time; for the work including the impression of a tooth profile, investment casting from the imitate profile by using metal or porcelain fused to metal to produce a tooth restoration, and finally the cementation of the tooth restoration. Normally, 7-10 working days are required for a complete therapy. In the meantime, the patient needs to wear a temporary tooth crown upon the abutment tooth to prevent any unexpected displacement and to perform a minimum chewing function. Such a tooth crown is needed and worn right after the abutment tooth is prepared. This temporary crown is made of resin and hardening glue, is prepared in the clinics by retrial and re-modified upon the abutment tooth, and is cemented by luting cement.
The work of forming an aforesaid resin crown is tedious and time-wasting. Therefore, a model crown as shown in FIG. 1 is promoted in the market. The model crowns 1 are manufactured in accordance variously with the profile and size of human teeth, incisors, premolars, and molars, and is numbered by a label 10. While using the model crowns, the dentist will firstly determine a proper model crown 1 according to patient's teeth condition, then set the model crown 1 by cement, finally cut the label 10 and polish.
Apparently, the usuage of the model crown 1 help the dentist away from the trivial process of forming a restoration, and provide the patient a more rapid dental therapy, especially saving a lot of time in keeping mouth open for retrying the restoration. However, this model crown 1 can only be applied to the patient with sick teeth, and is not applicable to patients with missing teeth. For the patient with a missing tooth, a temporary three-unit restoration bridge must be made in according to the extracted tooth and the adjacent teeth. At this situation, the model crown 1 is not useful, because the model crown 1 fails to have connection ability.
Therefore, an invention devoting to resolving the aforesaid disadvantages of the model crown or to the tooth restoration is necessary, definitely.